Question

what is refraction and why it occurs

Answer 1

Refraction is the bending of a light ray when it enters from one medium to another

This phenomena takes place bcz in speed of light changes when it goes from one medium to another ( speed of light is different in every medium)

Answer 2

Refraction is phenomenon of light when it travells from one medium to another. When the medium of light changes, it gets refracted from its path and this is called as refraction of light. This is due to change of speed of light in different media.